Your design is, by far, the most technically interesting
of the ones
submitted. It is also the only design that focused primarily on the safety
and preservation of human life, which is certainly a valuable contribution
to life aboard the station. I have a few technical questions about the
parts of the system you propose.

The first issue that comes to mind is one of scale. How
large is the
thermos-like chamber in which the carbon dioxide conversion would take
place? To what temperature would you have to heat the chamber? How much
energy would it take to heat the chamber, and would the bacteria produce
enough? If you know the size of the station, the size of the chamber,
and
the speed of the reaction, how long would it take for the robot to make
an
appreciable difference in the carbon dioxide levels? Also, do you have
a
spectrometer in mind? These tend to be quite large.

There is an actual project being done at the Johnson Space
Center that is
very similar to your idea for waste recycling. One of the issues that
they
are confronting is what to do with the matter they cannot recycle. Your
chamber takes in waste matter and puts out methane, but where does the
remaining matter go? How would you convert the methane into energy? Again,
how large would this compartment have to be?

How would the astronauts control the system? How would it
communicate its
results to the astronauts or to mission control?

You might consider sketching the robot to get a sense of
how large it
would be and how all of these parts would fit together.

Finally, if the robot moves both inside and outside, then
what type of
propulsion system would you use?